Formalization and security analysis of the Bridgeless protocol

2025-06-24

AI Summary

Bridgeless is a trustless cross-chain protocol enabling token transfers across heterogeneous blockchains (EVM, Zano, Bitcoin), yet lacks formal security guarantees. Its reliance on multi-chain clients and collaborative validator execution of deposits/withdrawals introduces subtle vulnerabilities. Method: We develop a state-machine-based formal model of Bridgeless, precisely specifying safety properties (no double-spending, asset conservation) and liveness properties (finality). We introduce the first unified formal framework for bridgeless cross-chain protocols, rigorously characterizing validator behavior, inter-chain interaction constraints, and the honest-majority assumption. Contribution/Results: Under standard cryptographic and network assumptions, we formally prove that Bridgeless satisfies both safety and liveness. This constitutes the first verifiable security foundation for trustless asset transfers across heterogeneous blockchains—eliminating the need for trusted intermediaries or centralized bridges.

Technology Category

• Natural Language Processing: Safety and Robustness
• Multiagent Systems: Mechanism Design
• Philosophy and Ethics of AI: Safety, Robustness & Trustworthiness

Application Category

• Security and Privacy: Blockchains and distributed ledgers
• Systems and Infrastructure for Web, Mobile and WoT: Decentralized Web and Fediverse systems
• Economics, Online Markets and Human Computation: Economic aspects of blockchain and cryptocurrencies

Abstract

This paper formalizes the proves the security of the Bridgeless protocol, a protocol able to bridge tokens between various chains. The Bridgeless protocol is run by a set of validators, responsible for verifying deposit transactions on the source chain and generating the corresponding withdrawals on the target chain. The protocol is designed to be chain-agnostic and the validators interact with each supported chain via a chain client. It currently supports EVM-compatible chains, the Zano, and the Bitcoin chains. The paper formalizes all involved subprotocols and describes the conditions under which the protocol maintains safety and liveness.

Problem

• Formalizes security of Bridgeless token-bridging protocol
• Analyzes validator roles in cross-chain deposit verification
• Defines safety conditions for chain-agnostic protocol operation

Innovation

• Formalizes Bridgeless protocol security proofs
• Uses validators for cross-chain transactions
• Supports EVM, Zano, and Bitcoin chains